Regeneration of selective hydrogenation catalyst



Patented Dec. 29, 1953 omirs'o sures smear crates,

lieu; Blatz; and Richa This; application: is a: continuation. in part of; application SeriallNonfifl'LOQh filed-June 15;,1946;, now: abandoned This-invention relatesvtoamethod: of reactivating; a catalytic material resistant; to ordinary poisons: yet. highly selective in. hydrogenation;

Catalysts employed. in hydrogenation; processes have: been. classified. as. sulfiuresensitive and. sule fur-insensitive; The: sulfur-sensitive; hydrogenation; catalysts: are highlyselective. and. intensely activdat low temperatures but lose; activity rapid? 1y when. contacte'di with: sulfur-containing feed; stocks... The suliur-insensitive catalysts. represented bychromium; or: molybdenum oxides and sulfides, are: used at relatively high temperatures for hydrogenation These. relatively high. tennperatur'c-s: result in cracking. which; leads: to ex".- cessive; formation of: low boiling. by-prcducts: and lowered: yields of the desired: saturated products1v The: nickel and: nobleimetal catalysts. have been. recognized: in; the art as belonging; to the; class: or": sulfur-sensitive hydrogenation catalysts which" catalyze hydrogenation": at temperatures below 400 E.,. but: in .th e iorm2 that these activecatalysts have been. used: they have been: toov readily poi soiled by traces of; organic peroxides, and. unsaturated polymers usually present in petroleum; productssubjected to:-hydrogenation These sulfur-sensitive catalysts have; a: life: toorshort for commercial, use and; are. not readily regenerated.

Aniobiect. of the present invention. is: toprovide a reactivated hydrogenation: catalyst which is relatively insensitive or: resistant ,to' sulfur poisoning;., yet:- sufficiently active sothat itis effective for selectively 'hydrogenating petroleum products at below; cracking temperatures. A more: specific object. ofi this invention is to provideasatisfactory methodofi regenerating the active sulfur-resistant catalytic material. which: selectively promotes hydrogenation of petroleum products: at below cracking temperatures.

Another object of the invention is'to-regenerate the catalyst by treatment with an oxygen containing. gas under conditions such that contaminating deposits are oxidized and driven. oft whilethe catalyst remains unoxi'dized'.

The catalytic material now determined tov possess: the desired selective hydrogenation char.- ac'teristics' with resistance to ordinary poisoning, comprises a minor proportion (0.1 to 10%. by weight) of a noble metal chosen from the group consisting of platinum and palladium depositedon an ultramicroscopic-pored bassgtypified by hydrou'sv oxides; such as silica and alumina.

The platin'ize'd' or palladiumized hydrous oxlde, base maybe prepared by mulling of the base with the colloidal noble metal followed by pellet- SELECTIVE HYDRG CATALYST rd 0. Brandon, Elizabeth: Na .L, assignors. to Standard Oil Development Companygva. corporation of Delaware.

sec-rewind Application All'gllst'ls; 1949,

- Serial- N0. 111,074;

3 Claims." (Cl. 251254131X ing or by mixing the base. with a saturated solui tion; of. an. acid; or salt: compound of the. metal; (e. g.,.in the case of platinum.chloroplatinicacid or ammonium ch1oroplatinate).,., followed wet. extrusion. of the The extruded pellets are driedand then. reduced. with: hydrogen: or. other reducing agent at. elevated: temperatures. The base inpowdered form. may be mixed Willi 1:601.- loicla-l particles.- 01 the. metal and. pilled in adryform. The pilled. or pelleted catalytic, material. may be used as such in a fixed bed type ofoperation or may be granulated to smaller size for use with a moving, or fluid type catalyst technique in obtaining selective hydrogenation of'petroleum products.

The sulfur-resistant catalytic materials conttaming platinum or palladium in the manner de-- scribed have been satisfactorily employed under specifically controlled conditions for selectively hydrogenating: organic peroxide. contaminants and diolefins in unsaturated hydrocarbon. stocks. They have also been. used. for selectively hydrogenating aromatic compounds; They have even been: found. very effective for: reduction. of; sulfur content. in: cracked; naphthasc, In: these low tern-- perature, low pressure? hydrogenation. processes. product recovery was substantially 100% in. all runs and the catalytic material was used for periods ranging up to about 100 hours; Also", under proper conditions, they have been used. for selectively" dehydrogenating hydro-aromatic compounds.

The following examples, not intended to be restrictive, are cited to show the regenerability of. the sulfur-resistant catalytic materials:

EXAMPLE. 1

Run number I Food I A. B

Temperature, F .l 300- 400 Pressure, p. s. i. g Atm. l: Atm. Liquid recovery, volume percent I00 100 100 Bromine: number of'reccvered condom l sate, cg/g I 91.5 90.8 9?.6.

at about 26% during the major portion of the regeneration period and during the final stages, was increased to about 20%. The temperature of the catalytic material initially was brought up to 700 F., then rose rapidly. By controlling the ratio of inert gas to air used in the manner indicated during the regeneration, the temperature was prevented from rising above 1100 F.

Tests showed that carbon dioxide was present.

in the regeneration gas as evidence that combuscatalyst.

tion of carbonaceous deposits was occurring.

No further carbon dioxide formation indicated that reactivation was completed. The platinum remained unoxidized during this regeneration and as shown by tests, therefore, did not require reduction prior to reuse.

Following the regeneration and without treatment of the catalyst with hydrogen or other reducing agent, some of the same trimer feed stock was treated with the regenerated catalytic material under the same conditions as set forth above to obtain the following data:

Primer plus 1,500 O. FJB. H2 at 1.0 v./v./hr.

Run number. 1. Feed D Tem erature, "F 300 400 lressu'e, p. s. i. g Atm. Atm. Liquid recovery, volume percent. 100 101 101 B rominc number of recovered condensate, l

cgJg 91.5 0.0

It will be noted that the regeneration markedly revivified the catalyst.

EXAMPLE 2 A sample of high-sulfur catalytically craked naphtha was treated with th sulfur-resistant catalytic material as follows:

Catalyst 2% platinum on alumina. Temperature. 600). Pressure. 100 IDS. per sq. in.

Hz ieed rate.

Hours on stream Feed 032 32-04 72-80 80-88 Condensate inspections: l

Bromine number, i l

cgjg 25.9 2.6 2.0 l 1.3 f 10.3 Sulfur, weight perl 1 cent 0. 143 O. 013 0.069 1 O. 115 O 121 material under identical conditions, the follow-.

ing results were obtained: Hours on stream H Feed \1 0-16 16-32 Condensate inspections:

Bromine number, cg./g 25. 9 0. 5 l 0.7 Su1iur,weight percent 143 0.001 0.002

A After regeneration.

As illustrated in the foregoing examples, the sulfur-resistant catalytic materials are satisfactorily regenerated by burning the carbonaceous deposits with a gas mixture of air or oxygen and a sumcient proportion of inert gas to control the regeneration temperature. The regeneration did not cause any deterioration of the catalytic material such as would generally be experienced in oxidizing, sintering, or fusing of finely-divided metal catalysts. The regenerated catalyst did not require reduction with hydrogen or the like prior to use in the productive phase, since the combustion of the contaminants during the regeneration did not cause oxidation of the noble metal, as determined by examination of the regenerated Satisfactory regeneration is very important in the commercial use of the precious metal catalysts.

Unlike intensely active hydrogenation catalysts that have been used in the past on pure hydrocarbons, the catalytic materials of interest in the present invention do not require a reduction step following their reactivation by oxidation of contaminating deposits and are not adversely affected by th presence of oxygen or oxidizing gases. Furthermore, any sulfiding or depositing of sulfur-containing compounds which may occur during the use of these catalytic materials does not prevent their ready reactivation by oxidation of such sulfur compounds and their removal from the catalyst under conditions indicated.

These readily regenerable sulfur-resistant catalytic materials have many important uses. They can b used with impure hydrogen, which is readily available and inexpensive in selective hydrogenation and purification treatments of various impure organic substances. The impure hydrogen may be a manufactured fuel gas containing sulfur, oxygen, and carbon monoxide, which have very adverse effects on the usual active and sulfur-sensitive catalysts.

The examples given are for the purpos of illustration and it will be understood that numerous modifications thereof, not specifically men tioned, come within the scope of the invention.

What is claimed is:

1. The method of reactivating compact pieces of catalytic material containing 0.1 to 10% by weight of a colloidal platinum group metal selected from the class consisting of platinum and palladium supported by a hydrous oxide carrier having ultramicroscopie pores after said catalytic material has become deactivated by carbonaceous deposits, which consists of heating the catalytic material to a temperature of approximately 700 F., contacting the catalytic material with a stream of inert gas mixed with oxygen in controlled amounts so that the platinum group metal is not oxidized and the temperature of the catalytic material does not substantially exceed 1100 F. during combustion of its deactivating deposits, the catalyst is not oxidized, sintered nor fused, and the catalyst is rendered suitable for reuse in the productive phase without necessitating a reduction step.

2. The method of reactivating a pelleted catalytic material containing 0.1 to 10% by weight of finely-divided platinum on alumina used for hydrogenating a petroleum product containing sulfur, which comprises burning deactivating deposits from the catalytic material by contact with an oxygen-containing gas at temperatures ranging from 700 F. to 1100 F., controlling the burning by maintaining the oxygen content of the oxygen-containing gas at from about 2-6% during the major part of the regeneration so that the platinum does not become oxidized by combustion of said deposits during the said combustion, thereafter increasing the oxygen content of the regeneration gas under such conditions that the platinum remains at a temperature of not over 1100 F., whereby the catalyst is rendered suitable for reuse in th productive phase without necessitating a reduction step.

3. The method of reactivating contact pieces of catalytic material containing 0.1 to 10% by weight of platinum supported on alumina which catalyst has been deactivated during the dehydrogenation of hydroaromatics by the accumulation of deactivating deposits thereon which comprises burning said deactivating deposits from the catalytic material by contact with an oxygencontaining gas and controlling the oxygen concentration of the said oxygen-containing gas during the reactivation so that the temperature of the catalytic material is maintained between 700 and 1100 F. during combustion of its deactivating deposits by utilizing air diluted with inert gas as the oxygen-containing gas during the LEO J. BLATZ. RICHARD C. BRANDON.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,207,868 Martin July 16, 1940 2,272,711 Hull Feb. 10, 1942 2,461,838 Neuhart Feb. 15, 1949 2,470,092 Corson et a1. May 1 1949 2,478,916 Haensel Aug. 16. 1949 OTHER REFERENCES Mellor: Comp. Treatis on Inorg. and Theor. Chem," vol. 16 (1937). p. 47. 

2. THE METHOD OF REACTIVATING A PELLETED CATALYTIC MATERIAL CONTAININER 0.1 TO 10% BY WEIGHT OF FINELY-DIVIDED PLATINUM OF ALUMINA USED FOR HYDROGENATING A PETROLEUM PRODUCT CONTAINING SULFUR, WHICH COMPRISES BURNING DEACTIVATING DEPOSITS FROM THE CATALYTIC MATERIAL BY CONTACT WITH AN OXYGEN-CONTAINING GAS AT TEMPERATURES RANGING FROM 700* F. TO 1100* F., CONTROLLING THE BURNING BY MAINTAINING THE OXYGEN CONTENT OF THE OXYGEN-CONTAINING GAS AT FROM ABOUT 2-6% DURING THE MAJOR PART OF THE REGENERATION SO THAT THE PLATINUM DOES NOT BECOME OXIDIZED BY COMBUSTION OF SAID DEPOSITS DURING THE SAID COMBUSTION, THEREAFTER INCREASING THE OXYGEN CONTENT OF THE REGENERATION GAS UNDER SUCH CONDITIONS THAT THE PLATINUM REMAINS AT A TEMPERATURE OF NOT OVER 1100* F., WHEREBY THE CATALYST IS RENDERED SUITABLE FOR REUSE IN THE PRODUCTIVE PHASE WITHOUT NECESSITATING A REDUCTION STEP. 